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{{Hyperkalemia }}
{{Hyperkalemia }}


{{CMG}}; [[Jogeet Singh Sekhon|{{AE}}Jogeet Singh Sekhon]]
{{CMG}}; {{AE}} {{JSS}} {{SAH}}
 
== Overview ==
== Overview ==
Serum potassium is the gold standard test for the diagnosis of hyperkalemia. [[Pseudohyperkalemia]] needs to be ruled out whenever hyperkalemia is diagnosed. Pseudohyperkalemia is defined when serum potassium concentration exceeds that of plasma. Different etiologies of hyperkalemia can be assessed by using the diagnostic criteria.
Serum [[potassium]] is the gold standard test for the [[diagnosis]] of hyperkalemia. [[Pseudohyperkalemia]] needs to be ruled out whenever hyperkalemia is diagnosed. Pseudohyperkalemia is defined when serum [[potassium]] concentration exceeds that of plasma. Different etiologies of [[hyperkalemia]] can be assessed by using the [[Diagnosis|diagnostic]] criteria.


== Diagnostic Study of Choice ==
== Diagnostic Study of Choice ==


=== Study of choice ===
=== Study of choice ===
Serum potassium is the gold standard test for the diagnosis of hyperkalemia.<ref name="pmid21181208">{{cite journal| author=Lehnhardt A, Kemper MJ| title=Pathogenesis, diagnosis and management of hyperkalemia. | journal=Pediatr Nephrol | year= 2011 | volume= 26 | issue= 3 | pages= 377-84 | pmid=21181208 | doi=10.1007/s00467-010-1699-3 | pmc=3061004 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=21181208  }} </ref>
* Serum [[potassium]] is the gold standard test for the [[diagnosis]] of hyperkalemia.<ref name="pmid21181208">{{cite journal| author=Lehnhardt A, Kemper MJ| title=Pathogenesis, diagnosis and management of hyperkalemia. | journal=Pediatr Nephrol | year= 2011 | volume= 26 | issue= 3 | pages= 377-84 | pmid=21181208 | doi=10.1007/s00467-010-1699-3 | pmc=3061004 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=21181208 }} </ref><ref name="pmid17848395">{{cite journal| author=Crop MJ, Hoorn EJ, Lindemans J, Zietse R| title=Hypokalaemia and subsequent hyperkalaemia in hospitalized patients. | journal=Nephrol Dial Transplant | year= 2007 | volume= 22 | issue= 12 | pages= 3471-7 | pmid=17848395 | doi=10.1093/ndt/gfm471 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=17848395 }} </ref>


There are two methods to determine serum potassium   :
*There are two methods to determine serum [[potassium]]:
* [[Flame emission spectrophotometry]]
**Ion-specific electrode (ISE) potentiometry
*ISE potentiometry has two different subtypes: direct (undiluted) and indirect (diluted).
**'''Direct ISE''' measures plasma [[potassium]] directly from a whole-blood sample and it's not associated with [[Pseudohyperkalemia|pseudohyperkalemia.]]
** FES or indirect ISE requires sample dilution before assay and both are associated with pseudohyperkalemia.


* Ion-specific electrode (ISE) potentiometry
=== Pseudohyperkalemia ===
ISE potentiometry has two different subtypes: direct (undiluted) and indirect (diluted).
* [[Pseudohyperkalemia]] is defined when serum [[potassium]] concentration exceeds that of plasma without any symptoms of hyperkalemia.
* '''Direct ISE''' measures plasma potassium directly from a whole-blood sample and it's not associated with pseudohyperkalemia.
 
* FES or indirect ISE requires sample dilution before assay and both are associated with pseudohyperkalemia.


=== Pseudohyperkalemia ===
* It usually occurs when [[potassium]] moves out of cells during blood specimen collection or during [[centrifugation]] of the sample.
[[Pseudohyperkalemia]] is defined when serum potassium concentration exceeds that of plasma without any symptoms of hyperkalemia.
* It usually occurs when potassium moves out of cells during blood specimen collection or during [[centrifugation]] of the sample.
* Other causes are [[thrombocytosis]], [[leukocytosis]] and [[Polycythemia|erythrocytosis]].
* Other causes are [[thrombocytosis]], [[leukocytosis]] and [[Polycythemia|erythrocytosis]].
* To rule out pseudohyperkalemia we need to do the following :<ref name="pmid29472808">{{cite journal| author=Šálek T| title=Pseudohyperkalemia - Potassium released from cells due to clotting and centrifugation - a case report. | journal=Biochem Med (Zagreb) | year= 2018 | volume= 28 | issue= 1 | pages= 011002 | pmid=29472808 | doi=10.11613/BM.2018.011002 | pmc=5806620 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=29472808  }} </ref>
* To rule out pseudohyperkalemia we need to do the following :<ref name="pmid29472808">{{cite journal| author=Šálek T| title=Pseudohyperkalemia - Potassium released from cells due to clotting and centrifugation - a case report. | journal=Biochem Med (Zagreb) | year= 2018 | volume= 28 | issue= 1 | pages= 011002 | pmid=29472808 | doi=10.11613/BM.2018.011002 | pmc=5806620 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=29472808  }} </ref>
** Repeat the blood sample.
** Repeat the blood sample.
**Complete blood count to rule out thrombocytosis, erythrocytosis and leukocytosis.
**[[Complete blood count]] to rule out [[thrombocytosis]], [[erythrocytosis]] and [[leukocytosis]].
**Measurement of plasma potassium and whole blood potassium.
**Measurement of [[Blood plasma|plasma]] [[potassium]] and whole blood [[potassium]].


===== Diagnostic results =====
===== Diagnostic results =====
The finding on performing the diagnostic test that confirms hyperkalemia 
* Serum [[Potassium]] level more than 5.1 meq/L<ref name="pmid28778861">{{cite journal| author=Montford JR, Linas S| title=How Dangerous Is Hyperkalemia? | journal=J Am Soc Nephrol | year= 2017 | volume= 28 | issue= 11 | pages= 3155-3165 | pmid=28778861 | doi=10.1681/ASN.2016121344 | pmc=5661285 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=28778861  }} </ref><ref name="pmid4625433">{{cite journal| author=Boddy K, King PC, Hume R, Weyers E| title=The relation of total body potassium to height, weight, and age in normal adults. | journal=J Clin Pathol | year= 1972 | volume= 25 | issue= 6 | pages= 512-7 | pmid=4625433 | doi= | pmc=477368 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=4625433  }} </ref>
* Serum Potassium level more than 5.1 meq/L.


== Common Diagnostic Studies ==
== Common Diagnostic Studies ==
The serum potassium must be performed when:
The serum [[potassium]] must be performed when:
* The patient presented with [[Cardiac arrhythmia|cardiac arrhythmias]], [[Muscle weakness|weakness]], [[fatigue]] and known case of [[Chronic renal failure|chronic kidney disease]]. The following investigations must be performed :  
* The [[patient]] presented with [[Cardiac arrhythmia|cardiac arrhythmias]], [[Muscle weakness|weakness]], [[fatigue]] and known case of [[Chronic renal failure|chronic kidney disease]]. The following investigations must be performed :
* Blood pressure(to look for [[hypoaldosteronism]])
* Blood pressure(to look for [[hypoaldosteronism]])
* Complete blood count
* [[Complete blood count]]
* Renal function tests
* [[Renal function tests]]
* Urine potassium,sodium and osmolality
* Urine [[potassium]],[[sodium]] and [[Osmolarity|osmolality]]
* Metabolic profile(other electrolytes)
* Metabolic profile(other [[electrolytes]])
* ECG
* [[The electrocardiogram|ECG]]
* [[Bicarbonate]] level
* [[Bicarbonate]] level
* Serum [[glucose]]
* Serum [[glucose]]
* Serum [[Calcium]]
* Serum [[calcium]]
Depending on the history and results of the above mentioned tests,other tests that can be performed for evaluating the cause of hyperkalemia.
 
* [[Digoxin]] level - If the patient is on a digitalis medication
Depending on the history and results of the above mentioned tests,other tests that can be performed for evaluating the cause of hyperkalemia <ref name="pmid7025622">{{cite journal| author=Adrogué HJ, Madias NE| title=Changes in plasma potassium concentration during acute acid-base disturbances. | journal=Am J Med | year= 1981 | volume= 71 | issue= 3 | pages= 456-67 | pmid=7025622 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=7025622  }} </ref><ref name="pmid8589279">{{cite journal| author=Allon M| title=Hyperkalemia in end-stage renal disease: mechanisms and management. | journal=J Am Soc Nephrol | year= 1995 | volume= 6 | issue= 4 | pages= 1134-42 | pmid=8589279 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=8589279  }} </ref>
* Arterial or venous [[Arterial blood gas|blood gas]]  
* [[Digoxin]] level - If the [[patient]] is on a digitalis medication
*[[Arterial blood gases|Arterial]] or [[venous]] [[Arterial blood gas|blood gas]]
* Urinalysis  
* Urinalysis  
* Serum [[Cortisol|cortiso]]<nowiki/>l and [[aldosterone]] levels  
* Serum [[Cortisol|cortiso]]<nowiki/>l and [[aldosterone]] levels  
* Serum [[uric acid]] and [[phosphorus]] assays  
* Serum [[uric acid]] and [[phosphorus]] assays  
* Serum [[Creatine kinase|creatinine phosphokinase]] (CPK) measurements
* Serum [[Creatine kinase|creatinine phosphokinase]] ([[CPK]]) measurements
* Urine [[myoglobin]] test  
* Urine [[myoglobin]] test  


=== Sequence of diagnostic studies ===
=== Sequence of diagnostic studies ===
* Serum Potassium measurement.
* Serum [[potassium]] measurement.
* ECG-it denotes the urgency of the treatment.
* [[ECG]]-it denotes the urgency of the treatment
* Renal function test.
* '''Renal function test.'''
**Serum [[Blood urea nitrogen|BUN]] and creatinine are measured.
**Serum [[Blood urea nitrogen|BUN]] and [[creatinine]] are measured
**Since creatinine levels are dependent on muscle mass so [[Glomerular filtration rate|GFR]] measurement is preferred.
**Since [[creatinine]] levels are dependent on muscle mass so [[Glomerular filtration rate|GFR]] measurement is preferred
* Urine potassium,sodium and [[Osmolarity|osmolality]] measurement.
* '''Urine potassium, sodium and osmolality measurement.'''
**Urine potassium measurement.
**'''Urine potassium measurement.'''
**Urine potassium <20meq/L denotes impaired excretion of potassium and denotes renal cause of hyperkalemia.
***Urine [[potassium]] < 20meq/L denotes impaired excretion of potassium and denotes renal cause of hyperkalemia.
**Urine potassium .40meq/L denotes adequate excretion of potassium and excludes renal cause of hyperkalemia.
***Urine [[potassium]] 40meq/L denotes adequate excretion of [[potassium]] and excludes renal cause of hyperkalemia.
**Urine sodium <20meq/L denotes decreased [[sodium]] delivery to the distal tubules which decreases potassium secretion.
**'''Urine sodium''' < 20meq/L denotes decreased [[sodium]] delivery to the distal tubules which decreases potassium secretion.
**Urine osmolarity-measuring urine osmolarity is very important for accurate measurement of urine potassium as concenterated or dilute urine will alter the urine potassium concenteration.
**'''Urine osmolarity'''-measuring urine osmolarity is very important for accurate measurement of urine potassium as concenterated or dilute urine will alter the urine [[potassium]] concentration.
* Serum osmolarity.
* '''Serum osmolarity'''
**High serum osmolarity(>295 mosm/kg) may result in extracellular shift of potassium .
**High serum [[osmolarity]] (>295 mosm/kg) may result in extracellular shift of [[potassium]] <ref name="pmid76227">{{cite journal| author=Viberti GC| title=Glucose-induced hyperkalaemia: A hazard for diabetics? | journal=Lancet | year= 1978 | volume= 1 | issue= 8066 | pages= 690-1 | pmid=76227 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=76227  }} </ref><ref name="pmid3084904">{{cite journal| author=Adrogué HJ, Lederer ED, Suki WN, Eknoyan G| title=Determinants of plasma potassium levels in diabetic ketoacidosis. | journal=Medicine (Baltimore) | year= 1986 | volume= 65 | issue= 3 | pages= 163-72 | pmid=3084904 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=3084904  }} </ref>
* Blood gas analysis .<ref name="pmid13242660">{{cite journal| author=SCRIBNER BH, FREMONT-SMITH K, BURNELL JM| title=The effect of acute respiratory acidosis on the internal equilibrium of potassium. | journal=J Clin Invest | year= 1955 | volume= 34 | issue= 8 | pages= 1276-85 | pmid=13242660 | doi=10.1172/JCI103174 | pmc=438696 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=13242660  }} </ref>
* Blood gas analysis: <ref name="pmid13242660">{{cite journal| author=SCRIBNER BH, FREMONT-SMITH K, BURNELL JM| title=The effect of acute respiratory acidosis on the internal equilibrium of potassium. | journal=J Clin Invest | year= 1955 | volume= 34 | issue= 8 | pages= 1276-85 | pmid=13242660 | doi=10.1172/JCI103174 | pmc=438696 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=13242660  }} </ref>
**Decreased serum pH causes extracellular shift of potassium into the blood.
**Decreased serum [[pH]] causes [[extracellular]] shift of [[potassium]] into the [[blood]]
* Transtubular Potassium gradient.
* '''Transtubular potassium gradient''' <ref name="pmid18216310">{{cite journal| author=Choi MJ, Ziyadeh FN| title=The utility of the transtubular potassium gradient in the evaluation of hyperkalemia. | journal=J Am Soc Nephrol | year= 2008 | volume= 19 | issue= 3 | pages= 424-6 | pmid=18216310 | doi=10.1681/ASN.2007091017 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=18216310  }} </ref><ref name="pmid2321642">{{cite journal| author=Ethier JH, Kamel KS, Magner PO, Lemann J, Halperin ML| title=The transtubular potassium concentration in patients with hypokalemia and hyperkalemia. | journal=Am J Kidney Dis | year= 1990 | volume= 15 | issue= 4 | pages= 309-15 | pmid=2321642 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=2321642  }} </ref>
**It calculates the ratio of amount potassium in the [[Collecting duct system|collecting duct]] of kidneys with the amount of potassium in the [[peritubular capillaries]].
**It calculates the ratio of amount [[potassium]] in the [[Collecting duct system|collecting duct]] of kidneys with the amount of [[potassium]] in the [[peritubular capillaries]]
**It indicates the activity of [[aldosterone]] on kidneys in regulation of potassium levels.
**It indicates the activity of [[aldosterone]] on [[kidneys]] in regulation of [[potassium]] levels
**TTG calculation-( Urine K<sup>+</sup> x Serum osmolarity)/(serum K<sup>+</sup> x Urine omolarity).
**TTG calculation-( Urine K<sup>+</sup> x Serum [[osmolarity]])/(serum K<sup>+</sup> x Urine [[osmolarity]])
**TTG <3 suggests lack of [[aldosterone]] effect on [[Collecting duct system|collecting ducts]] causing decreased excretion of potassium.
**TTG <3 suggests lack of [[aldosterone]] effect on [[Collecting duct system|collecting ducts]] causing decreased excretion of potassium
**TTG >7 suggest adequate effect of aldosterone in a case of hyperkalemia.
**TTG >7 suggest adequate effect of aldosterone in a case of hyperkalemia
**If TTG suggest [[aldosterone]] etiology then further testing done.
**If TTG suggest [[aldosterone]] etiology then further testing done
*Aldosterone levels
*[[Aldosterone]] levels
*Renin levels <ref name="pmid2402122">{{cite journal| author=Conte G, Dal Canton A, Imperatore P, De Nicola L, Gigliotti G, Pisanti N et al.| title=Acute increase in plasma osmolality as a cause of hyperkalemia in patients with renal failure. | journal=Kidney Int | year= 1990 | volume= 38 | issue= 2 | pages= 301-7 | pmid=2402122 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=2402122  }} </ref>
*[[Renin]] levels <ref name="pmid2402122">{{cite journal| author=Conte G, Dal Canton A, Imperatore P, De Nicola L, Gigliotti G, Pisanti N et al.| title=Acute increase in plasma osmolality as a cause of hyperkalemia in patients with renal failure. | journal=Kidney Int | year= 1990 | volume= 38 | issue= 2 | pages= 301-7 | pmid=2402122 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=2402122  }} </ref>
 
 
 
== Diagnostic criteria ==
== Diagnostic criteria ==
{{Family tree/start}}
{{Family tree/start}}
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{{Family tree | | | | | | | | | | | | | | B01 | | | | | | | | | | | B01= ECG }}
{{Family tree | | | | | | | | | | | | | | B01 | | | | | | | | | | | B01= ECG }}
{{Family tree | | | | | | | | | | | | |,|-|^|-|.| | | | | | | | | | }}
{{Family tree | | | | | | | | | | | | |,|-|^|-|.| | | | | | | | | | }}
{{Family tree | | | | | | | | | | | | C01 | | C02 | | | | | | | | | C01=If no changes,rule out pseudohyperkalemia| C02= If changes present then start urgent treatment}}  
{{Family tree | | | | | | | | | | | | C01 | | C02 | | | | | | | | | C01=If no changes,rule out [[pseudohyperkalemia]]| C02= If changes present then start urgent treatment}}  
{{Family tree | | | | | | | |,|-|-|-|-|^|-|-|-|-|.| | | | | | | | |}}
{{Family tree | | | | | | | |,|-|-|-|-|^|-|-|-|-|.| | | | | | | | |}}
{{Family tree | | | | | | | D01 | | | | | | | D02 |D01=Urine sodium <25 meq/L|D02=urine sodium >25 meq/L }}
{{Family tree | | | | | | | D01 | | | | | | | D02 |D01=Urine sodium <25 meq/L|D02=urine sodium >25 meq/L }}
{{Family tree | | | | | | | |!| | | |,|-|-|-|-|^|-|-|-|-|.| | | | | }}
{{Family tree | | | | | | | |!| | | |,|-|-|-|-|^|-|-|-|-|.| | | | | }}
{{Family tree | | | | | | | E01 | | E02 | | | | | | | | E03 | | | | | | | E01=ARF<br>CKD<br>Heart failure<br>Volume depletion|E02=Decreased K+secretion(Urine K+<20meq/L|E03=Transcellular shift(measure serum osmolarity and pH) }}
{{Family tree | | | | | | | E01 | | E02 | | | | | | | | E03 | | | | | | | E01=ARF<br>CKD<br>[[Heart failure]],<br>Volume depletion|E02=Decreased K+secretion(Urine K+<20meq/L|E03=Transcellular shift(measure serum osmolarity and pH) }}
{{familytree  | | | | | | |,|-|-|-|-|^|-|-|.| | | | | | |!| | | | | | | | }}
{{familytree  | | | | | | |,|-|-|-|-|^|-|-|.| | | | | | |!| | | | | | | | }}
{{Family tree | | | | | | F01 | | | | | | F02 | | | | | F03 | | | | | | F01=Low aldosterone(TTG<3)|F02=Normal aldosterone(TTG>7)|F03=Diabetic ketoacidosis<br>Metabolic acidosis}}
{{Family tree | | | | | | F01 | | | | | | F02 | | | | | F03 | | | | | | F01=Low [[aldosterone]](TTG<3)|F02=Normal aldosterone(TTG>7)|F03=[[Diabetic ketoacidosis]],<br>Metabolic [[acidosis]]}}
{{Family tree | | | | |,|-|^|-|.| | | | | |!| | | | | | | | | | | }}
{{Family tree | | | | |,|-|^|-|.| | | | | |!| | | | | | | | | | | }}
{{Family tree | | | | G01 | | G02 | | | | G03 | | | | | | | | | | G01=Low renin|G02=Normal renin|G03=Tissue breakdown<br>Pseudohypoaldosternism type 1 and type 2<br>Type 1 RTA }}
{{Family tree | | | | G01 | | G02 | | | | G03 | | | | | | | | | | G01=Low [[renin]]|G02=Normal renin|G03=Tissue breakdown,<br>[[Pseudohypoaldosternism]] type 1 and type 2,<br>Type 1 [[RTA]] }}
{{Family tree | | | | |!| | | |!| | | | | | | | | | | | }}
{{Family tree | | | | |!| | | |!| | | | | | | | | | | | }}
{{Family tree | | | | H01 | | H02 | | | | | | | | | H01=Interstital nephritis<br>Obstructive uropathies<br>Diabetic nephropathy<br>ACE inhibitors,Angiotensin 2 receptors|H02=Primary hypoaldosteronism<br>Congenital adrenal hyperplasia<br>Aldosterone receptor antagonists<br>RTA type 4
{{Family tree | | | | H01 | | H02 | | | | | | | | | H01=[[Interstital nephritis]],<br>[[Obstructive uropathies]],<br>[[Diabetic nephropathy]],<br>[[ACE inhibitors]],Angiotensin 2 receptors|H02=Primary [[hypoaldosteronism]],<br>[[Congenital adrenal hyperplasia]],<br>Aldosterone receptor antagonists,<br>RTA type 4
}}
}}
{{familytree/end}}
{{familytree/end}}


==References==
==References==
{{Reflist|2}}
{{Reflist|2}}
{{WH}}
{{WS}}
<references />

Latest revision as of 22:32, 29 April 2020


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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Jogeet Singh Sekhon, M.D. [2] Syed Ahsan Hussain, M.D.[3]

Overview

Serum potassium is the gold standard test for the diagnosis of hyperkalemia. Pseudohyperkalemia needs to be ruled out whenever hyperkalemia is diagnosed. Pseudohyperkalemia is defined when serum potassium concentration exceeds that of plasma. Different etiologies of hyperkalemia can be assessed by using the diagnostic criteria.

Diagnostic Study of Choice

Study of choice

  • There are two methods to determine serum potassium:
    • Ion-specific electrode (ISE) potentiometry
  • ISE potentiometry has two different subtypes: direct (undiluted) and indirect (diluted).
    • Direct ISE measures plasma potassium directly from a whole-blood sample and it's not associated with pseudohyperkalemia.
    • FES or indirect ISE requires sample dilution before assay and both are associated with pseudohyperkalemia.

Pseudohyperkalemia

Diagnostic results

Common Diagnostic Studies

The serum potassium must be performed when:

Depending on the history and results of the above mentioned tests,other tests that can be performed for evaluating the cause of hyperkalemia [6][7]

Sequence of diagnostic studies

  • Serum potassium measurement.
  • ECG-it denotes the urgency of the treatment
  • Renal function test.
  • Urine potassium, sodium and osmolality measurement.
    • Urine potassium measurement.
      • Urine potassium < 20meq/L denotes impaired excretion of potassium and denotes renal cause of hyperkalemia.
      • Urine potassium 40meq/L denotes adequate excretion of potassium and excludes renal cause of hyperkalemia.
    • Urine sodium < 20meq/L denotes decreased sodium delivery to the distal tubules which decreases potassium secretion.
    • Urine osmolarity-measuring urine osmolarity is very important for accurate measurement of urine potassium as concenterated or dilute urine will alter the urine potassium concentration.
  • Serum osmolarity
  • Blood gas analysis: [10]
  • Transtubular potassium gradient [11][12]
  • Aldosterone levels
  • Renin levels [13]

Diagnostic criteria

 
 
 
 
 
 
 
 
 
 
 
 
 
Potassium >5.1meq/L
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
ECG
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
If no changes,rule out pseudohyperkalemia
 
If changes present then start urgent treatment
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Urine sodium <25 meq/L
 
 
 
 
 
 
urine sodium >25 meq/L
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
ARF
CKD
Heart failure,
Volume depletion
 
Decreased K+secretion(Urine K+<20meq/L
 
 
 
 
 
 
 
Transcellular shift(measure serum osmolarity and pH)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Low aldosterone(TTG<3)
 
 
 
 
 
Normal aldosterone(TTG>7)
 
 
 
 
Diabetic ketoacidosis,
Metabolic acidosis
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Low renin
 
Normal renin
 
 
 
Tissue breakdown,
Pseudohypoaldosternism type 1 and type 2,
Type 1 RTA
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Interstital nephritis,
Obstructive uropathies,
Diabetic nephropathy,
ACE inhibitors,Angiotensin 2 receptors
 
Primary hypoaldosteronism,
Congenital adrenal hyperplasia,
Aldosterone receptor antagonists,
RTA type 4
 
 
 
 
 
 
 
 

References

  1. ↑ Lehnhardt A, Kemper MJ (2011). "Pathogenesis, diagnosis and management of hyperkalemia". Pediatr Nephrol. 26 (3): 377–84. doi:10.1007/s00467-010-1699-3. PMC 3061004. PMID 21181208.
  2. ↑ Crop MJ, Hoorn EJ, Lindemans J, Zietse R (2007). "Hypokalaemia and subsequent hyperkalaemia in hospitalized patients". Nephrol Dial Transplant. 22 (12): 3471–7. doi:10.1093/ndt/gfm471. PMID 17848395.
  3. ↑ Šálek T (2018). "Pseudohyperkalemia - Potassium released from cells due to clotting and centrifugation - a case report". Biochem Med (Zagreb). 28 (1): 011002. doi:10.11613/BM.2018.011002. PMC 5806620. PMID 29472808.
  4. ↑ Montford JR, Linas S (2017). "How Dangerous Is Hyperkalemia?". J Am Soc Nephrol. 28 (11): 3155–3165. doi:10.1681/ASN.2016121344. PMC 5661285. PMID 28778861.
  5. ↑ Boddy K, King PC, Hume R, Weyers E (1972). "The relation of total body potassium to height, weight, and age in normal adults". J Clin Pathol. 25 (6): 512–7. PMC 477368. PMID 4625433.
  6. ↑ Adrogué HJ, Madias NE (1981). "Changes in plasma potassium concentration during acute acid-base disturbances". Am J Med. 71 (3): 456–67. PMID 7025622.
  7. ↑ Allon M (1995). "Hyperkalemia in end-stage renal disease: mechanisms and management". J Am Soc Nephrol. 6 (4): 1134–42. PMID 8589279.
  8. ↑ Viberti GC (1978). "Glucose-induced hyperkalaemia: A hazard for diabetics?". Lancet. 1 (8066): 690–1. PMID 76227.
  9. ↑ Adrogué HJ, Lederer ED, Suki WN, Eknoyan G (1986). "Determinants of plasma potassium levels in diabetic ketoacidosis". Medicine (Baltimore). 65 (3): 163–72. PMID 3084904.
  10. ↑ SCRIBNER BH, FREMONT-SMITH K, BURNELL JM (1955). "The effect of acute respiratory acidosis on the internal equilibrium of potassium". J Clin Invest. 34 (8): 1276–85. doi:10.1172/JCI103174. PMC 438696. PMID 13242660.
  11. ↑ Choi MJ, Ziyadeh FN (2008). "The utility of the transtubular potassium gradient in the evaluation of hyperkalemia". J Am Soc Nephrol. 19 (3): 424–6. doi:10.1681/ASN.2007091017. PMID 18216310.
  12. ↑ Ethier JH, Kamel KS, Magner PO, Lemann J, Halperin ML (1990). "The transtubular potassium concentration in patients with hypokalemia and hyperkalemia". Am J Kidney Dis. 15 (4): 309–15. PMID 2321642.
  13. ↑ Conte G, Dal Canton A, Imperatore P, De Nicola L, Gigliotti G, Pisanti N; et al. (1990). "Acute increase in plasma osmolality as a cause of hyperkalemia in patients with renal failure". Kidney Int. 38 (2): 301–7. PMID 2402122.
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